Sense Number 1: a system of interconnected social entities,e.g., people, organizations

Examples:
His family has built up a network of inexpensive motor inns throughout the midwest.
John studied social network theory in college.
She has an extensive network of friends both here and in Europe.
The spy network they uncovered had been working inside the Beltway for a decade.

Examples:
A French network was the first to run the story.
Sally never watches network television.
The networks are losing market share every year to the cable companies.
Network executives were outraged at the performance during the Super Bowl half time show.

Mappings:WordNet 3.0 Sense Numbers: 2

Sense Number 3: a physical system of interconnected components

Commentary: NETWORK[+entity][+system][+interconnected][+physical][+line][+electromagnetic[+circuit/+signal/+wire]/+land[+rail/+road]/+water[+canal]]
NOTE: focus is on the medium of transport, -not- the business of disseminating content (see Sense 2)

Examples:
The network of wires and cables in a modern aircraft is large and complex.
We travelled through France on the network of old canals still in existence.
That country's network of roads is in a state of serious decay.
Neural networks in the brain are still not well understood.
The topology of this network is a token ring.
ABC Network said their network went down in Boston because of the ice storm. (second instance is this sense)
Solar flares sometimes cause problems for satellite communication networks.
John set up a a local area network for his family.
Skeptics believe the story is just a network of lies concocted by political cronies. (metaphoric use)

Mappings:WordNet 3.0 Sense Numbers: 4, 5

Sense Number 4: a mesh-like fabric or substance

Examples:
The hammock consisted of a course network of rope, slung up between two trees.
The fine mesh bag was a network of nylon threads, loosely woven together.
A network of spidery small veins were apparent in his cheeks.